Our long term goal is to establish SaMi-Trop as a Center of Excellence for Neglected Infectious Disease Research in Brazil. The Specific Aims of the current application are to begin that process by focusing on T. cruzi infection with the goal of finding an array of biomarkers that correlate with parasite persistence and Chagas cardiac disease that can be used to infer risk of disease progression and death as well used as surrogate markers of cure or efficacy of novel drugs. We will develop three interrelated studies: Project 1 will focus on applying gene expression tools to existing whole blood RNA samples from the NHLBI REDS-II cohort to discover and validate new biomarkers of active infection and disease progression, these will be combined with parasite specific (PCR load and antibody profiling and titers) and plasma proteomic biomarkers (chemokines, cytokines, and inflamatory, coagulation and cardiac parameters) that are being generated through already funded collaborations, to generate composite biomarker profiles and scores that coorelate with pre-defined disease stages. In Project 2 we plan to treat a subgroup of 100 T cruzi PCR-positive patients from the REDS-II cohort using standard treatment with benznidazole (BZN) and follow subjects for 2 years after treatment. We will use these samples to validate the utility of biomarkers and composite biomarker profiles found in project 1 for assessment of therapeutic responses including clearance or suppression of parasitemia or normalization of immune perturbations and markers of cardiac damage. In Project 3 we plan to take advantage of the Public Health System in the State of Minas by enrolling and collecting blood samples from 2000 Chagas disease patients. These patients will be followed for two years for the endpoints of death or admission to a hospital for cardiac disease. The main goal is to obtain a simple risk score based on biomarker levels and ECG fndings that could identify high risk patients in order to guide therapeutic approaches and serve as a foundation for future clinical trials. Two cores will be established: the Administrative Core and Database and Epidemiology Core that will support activities of the 3 projects, as well as create and sustain research training capacity for young Brazilian scientists.